scholarly journals THE EFFICIENCY OF THE WATER PURIFICATION PROCESS FROM BACTERIA DEPENDING ON THE GAS NATURE

2021 ◽  
pp. 41-44
Author(s):  
Iryna Koval
Keyword(s):  
Carbon Dioxide ◽  
Water Treatment ◽  
Water Purification ◽  
High Efficiency ◽  
Total Duration ◽  
Reaction Medium ◽  
Microbial Count ◽  
Bacterial Cells ◽  
Subsequent Decrease ◽  
Number Of Microorganisms

A study of the influence of different gas nature on the efficiency of water purification from rod-shaped bacteria of the Bacillus cereus type is presented. The action of oxygen, carbon dioxide and inert argon and helium were used. The investigated water was model microbial water obtained on the basis of deaerated distilled water with the introduction of a pure culture of bacteria in the amount of 7 · 104 CFU/cm3. The total duration of the process was 2 hours at a reaction medium with temperature of 288 ± 1 K. The change in the number of microorganisms from the duration of gas bubbling is shown, depending on its nature. The degrees of destroyed microorganisms were calculated after each sampling of water (Dd), which was taken after each 30 min of the process. Studying the influence of different modes of water treatment, the largest number of destroyed bacterial cells was studied in an atmosphere of carbon dioxide (Dd = 91.0 %), and the smallest - in an atmosphere of oxygen (Dd = 34.73%). A two-stage process of number of microorganisms change was detected in the oxygen atmosphere: an increase in the first stage during 1800 s and a subsequent decrease in the second stage. After CO2 bubbling with a rate of 0.2 cm3/s through an aqueous medium with a volume of 75 cm3, the microbial count decreased by two orders of magnitude, which is apparently due to an increase in the acidity of the test medium. Having found a high efficiency of CO2 on the process of bacterial cells destruction, this gas should be used in water treatment processes, as well as in combination with other reagents or physical methods of water treatment to enhance the destructive effect on micro-objects.

scholarly journals Water disinfection under the helium influence

2021 ◽  
Vol 4 (3(60)) ◽  
pp. 6-8
Author(s):  
Iryna Koval
Keyword(s):  
Natural Waters ◽  
Unit Volume ◽  
Aqueous Media ◽  
Reaction Medium ◽  
Research Process ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Treatment Technology ◽  
Running Water ◽  
Number Of Microorganisms

The object of research is the process of water disinfection at the influence of gas from bacteria of a particular genus with different amounts per unit volume of water. Due to the annual increase in the amount of pollutants in natural waters, new opportunities to improve microbiological indicators of water quality are being explored. There are many different ways to disinfect it, both physical and chemical. However, no single method has been found to purify aqueous media from microorganisms that would ensure their effective destruction. It is proposed to study the activity of specific microorganisms during the bubbling of inert gas through the aqueous medium. The microorganisms studied were rod-shaped sporogenic cells of Bacillus cereus bacteria type. The test gas was inert helium. The study used continuous gas bubbling throughout the process, which allowed to mix microbial water efficiently and prevent the formation of stagnant zones in the reaction medium. In particular, active gas mixing facilitates its access to each cell. The gas supply rate corresponded to 0.2 cm3/s, and its flow rate was 0.7 dm3 for one hour of bubbling through microbial water. The duration of the entire research process was 7200 s. The constant temperature of the microbial water (T=288±1 K) was maintained during the experiment by cooling the glass reactor with running water. An in-depth method of culturing bacterial cells was used. A decrease in the number of microorganisms was observed throughout the helium supply process, despite the different initial amounts in the water. The highest destruction degree of bacillus (77.06 %) was obtained at the lowest studied concentration in water (NM01=3.4·104 CFU/cm3). This is due to the fact that less microbial load provides better conditions for access of helium to the cell and their effective destruction. The proposed method of water purification allowed to achieve a sufficiently high degree of water disinfection from sporogenic rod-shaped bacteria after the action of helium alone. In particular, it has been experimentally proven that the efficiency of the water disinfection process depends on the concentration of microorganisms per unit volume of water. Due to the treatment of contaminated water with gas, it is possible to obtain high rates of its purification and the application of this method for practical purposes in water treatment technology.

scholarly journals Influence of Aerobic Bacteria Concentration on the Process of its Survival in the Presence of Oxygen

2020 ◽  
Keyword(s):  
Unit Volume ◽  
Aqueous Media ◽  
Oxygen Atmosphere ◽  
Aerobic Bacteria ◽  
Bacterial Cells ◽  
High Concentration ◽  
Aquatic Medium ◽  
Subsequent Decrease ◽  
Before And After ◽  
Number Of Microorganisms

Purpose of the study is to study the viability of aerobic microorganisms in an oxygen atmosphere with different initial content in the aquatic medium. Compare the effect of gas on different concentrations of bacteria per unit volume of the water. Methods. Aerobic bacteria of the genus Bacillus cereus bacteria type were the studied microorganisms. Model aqueous media were created on the basis of distilled deaerated water with the addition of bacteria of a particular type. Oxygen was bubbled into the microbial water throughout the process at a rate of 0.2 cm3/s. The duration of the study was 2 hours, during which the total gas consumption corresponded to 1.4 dm3. The number of microorganisms (NM) before and after the experiments was determined by counting the colonies that grew on the Petri dishes. Results. A two-stage process of oxygen exposure to aerobic bacteria was detected - accumulation and reduction of its number per unit volume of water during all experiments. At the first stage of the process, there was an increase of NM during 1800-3600 s with its subsequent decrease (II stage). With an increase in the microbial load in the water from 102 to 104 CFU/cm3, the duration of the process of bacterial accumulation was decreased in two times. An active reproduction of bacterial cells was investigated at the low concentration of bacteria in the water, and its active reduction - at the high concentration that is explained by cells destruction under conditions of constant supply of oxygen of the established rate. Conclusions. The oxygen influence on the change of the number of aerobic microorganisms in the aquatic medium is explained. It is investigated that the oxygen action on bacteria in the water divides the process of its viability into two stages: accumulation (I stage) and reduction of its number (II stage). It is shown that the duration of the process of bacteria accumulation in the oxygen atmosphere depends on its initial amount in the water, namely with increasing of the initial NM per unit volume of the water, the duration of the stage of microorganisms accumulation decreases significantly.

scholarly journals Viability of sporogenic bacteria in an inert gas atmosphere

2020 ◽  
Vol 12 (1) ◽  
pp. 8-13
Author(s):  
Iryna Koval
Keyword(s):  
Water Purification ◽  
Rate Constants ◽  
Unit Volume ◽  
Water System ◽  
Effective Rate ◽  
Inert Gases ◽  
Water Volume ◽  
Microbial Count ◽  
Order Kinetic ◽  
Number Of Microorganisms

The viability of sporogenic bacteria under the conditions of bubbling inert gases (argon and helium) through the water system was investigated and the action of each studied gases on the process of its destruction in water was compared. Bacillus cereus bacteria type were as the investigated microobjects and, as the predominant microflora of different natural waters, with an initial microbial load of 104 per 1 cm3 of investigated water. According with the first-order kinetic equation were calculated the values of the effective rate constants of the bacteria destruction. The effective gas nature in the process of water purification from microorganisms is noted. The experiments were carried out in a glass reactor with constant cooling of tap water. The growth of the investigated bacteria were carried out by the deep method, followed by storage in a thermostat at T = 30 °C for 48 h. The number of microorganisms per unit volume of investigated water was determined by the total number of bacteria grown on the culture medium on Petri dishes and expressed in colony-forming units. The total flow rate of the bubbled gas was 1.4 dm3, which was fed at a rate of 0.2 cm3/s to the investigated water volume (75 cm3) throughout the duration of the process. The calculated total microbial count in natural water and various industrial wastewater was used to determine the initial number of microorganisms per unit volume of investigated water. The dynamics of bacterial numbers under the influence of gases on the water system is presented graphically. Colonies of B. cereus bacteria type are presented during growth on nutrient medium before and after bubbling of microbial water with gas. Decreasing of the bacterial cells number was observed in the atmosphere of both investigated gases, but with different activity. Comparison of the values of the effective rate constants of bacteria for argon and helium showed that the cell number decreased more actively under argon bubbling conditions. Active destruction of microorganisms under argon bubbling compared to helium was observed, regardless of the initial bacterial count in 1 cm3 of investigated water. The effect of argon on water containing bacteria is described by the greater value of the effective rate constant of cell destruction: kd(Ar) > kd(He). It is shown that the efficiency of water purification from microorganisms depends on the nature of the bubbled gas.

scholarly journals The Influence of Helium And Cavitation on the Yeast Life Process

2021 ◽  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Water Treatment ◽  
Water Purification ◽  
Tap Water ◽  
Pure Water ◽  
Total Duration ◽  
Water System ◽  
Yeast Cells ◽  
Experimental Conditions ◽  
Test Water

Purpose of the study is to іnvestigate the simultaneous effect of cavitation and helium on the viability of yeast of the genus Saccharomyces cerevisiae in water. To study the change in the number of cells during cavitation treatment of the water system in the gas atmosphere. Methods. Yeast of Saccharomyces cerevisiae type were used as test microorganisms. Freshly prepared distilled desaerated water was used for the research, to which yeast cells were introduced with a microbiological loop. The volume of the model medium was cooled in a glass reactor with tap water, the temperature of which corresponded to 298 ± 1 K. The total duration of the process was 2 hours. The cavitation source was an ultrasonic generator UZDN-2T with frequency of 22 kHz and power of 35 W. The test water was bubbled with gas throughout the process. The test gas was helium. The number of microorganisms per unit volume of test water was determined by the total number of colonies on the nutrient medium on Petri dishes and expressed in colony-forming units (CFU). Results. In the experimental part of the work the process of water treatment with the content of yeast cells under cavitation conditions with simultaneous supply of helium is proposed. The efficiency of water purification from yeast as a result of the combined action of helium/cavitation has been established. The value of the effective rate constant of microorganisms destruction according to the kinetic reaction equation of the first order is calculated. The viability of yeast under cavitation conditions and bubbling of helium through the water system has been studied. The proportion of destroyed cells during the two-hour action of yeast-contaminated water at different treatment regimes was calculated and compared. An active decrease in the number of Saccharomyces cerevisiae in the aqueous medium at the beginning of the process with the achievement of the proportion of destroyed cells (Dd) 40.48% after 30 min of combined He/cavitation action at the initial microbiological water contamination of 4.2 · 103 CFU/cm3. NMend = 100 CFU/cm3 after 90 minutes of water treatment, that corresponds to the water purification degree > 97%. The end result is almost pure water, which allows to discharge treated water into natural water. Conclusions. The obtained results indicate intensive cavitation purification of water from the studied microorganisms in the experimental conditions. The influence of the studied gas nature on the process of destruction of microbiological contaminants in water is described.

scholarly journals Comparison the effectiveness of using a magnetic field to control theColi phages isolated from rivulet water with water-treatment using magnetic field added iron filings

2014 ◽  
Vol 11 (3) ◽  
pp. 1361-1366
Author(s):  
Baghdad Science Journal
Keyword(s):  
Magnetic Field ◽  
Water Treatment ◽  
Water Purification ◽  
High Efficiency ◽  
Negative Impact ◽  
Waste Water Treatment ◽  
High Surface ◽  
High Surface Area ◽  
Wide Range ◽  
The Magnetic Field

The present study aimed to use the magnetic field and nanotechnology in the field of water purification, which slots offering high efficiency to the possibility of removing biological contaminants such as viruses and bacteria rather than the use of chemical and physical transactions such as chlorine and bromine, and ultraviolet light and boiling and sedimentation and distillation, ozone and others that have a direct negative impact on human safety and the environment. Where they were investigating the presence in water samples under study Coli phages using Single agar layer method and then treated samples positive for phages to three types of magnetic field fixed as follows (North Pole - South Pole - Bipolar) and compare the results with samples of water treatment in the same conditions of the magnetic field with the addition of powder iron filings stated the results to the act synergistic to use a magnetic field with iron filling efficiency up to 100% better than the use of a magnetic field alone, where the disappearance of the emergence of spots Plaques treatment in the second. thus enhancing the possibility of making iron pipe nanoparticles to pump water in the treatment of water due to the high surface area (surface / volume). It is suggested that this could be used in the future in a wide range of water purification may be the best option for waste water treatment.

scholarly journals Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1338 ◽  
Author(s):  
Klara Perović ◽  
Francis M. dela Rosa ◽  
Marin Kovačić ◽  
Hrvoje Kušić ◽  
Urška Lavrenčič Štangar ◽  
...  
Keyword(s):  
Water Treatment ◽  
Transition Metal ◽  
Photocatalytic Degradation ◽  
Water Splitting ◽  
Water Purification ◽  
Degradation Mechanism ◽  
Living Environment ◽  
Solar Irradiation ◽  
Metal Chalcogenides ◽  
Photocatalytic Water Splitting

Clean water and the increased use of renewable energy are considered to be two of the main goals in the effort to achieve a sustainable living environment. The fulfillment of these goals may include the use of solar-driven photocatalytic processes that are found to be quite effective in water purification, as well as hydrogen generation. H2 production by water splitting and photocatalytic degradation of organic pollutants in water both rely on the formation of electron/hole (e−/h+) pairs at a semiconducting material upon its excitation by light with sufficient photon energy. Most of the photocatalytic studies involve the use of TiO2 and well-suited model compounds, either as sacrificial agents or pollutants. However, the wider application of this technology requires the harvesting of a broader spectrum of solar irradiation and the suppression of the recombination of photogenerated charge carriers. These limitations can be overcome by the use of different strategies, among which the focus is put on the creation of heterojunctions with another narrow bandgap semiconductor, which can provide high response in the visible light region. In this review paper, we report the most recent advances in the application of TiO2 based heterojunction (semiconductor-semiconductor) composites for photocatalytic water treatment and water splitting. This review article is subdivided into two major parts, namely Photocatalytic water treatment and Photocatalytic water splitting, to give a thorough examination of all achieved progress. The first part provides an overview on photocatalytic degradation mechanism principles, followed by the most recent applications for photocatalytic degradation and mineralization of contaminants of emerging concern (CEC), such as pharmaceuticals and pesticides with a critical insight into removal mechanism, while the second part focuses on fabrication of TiO2-based heterojunctions with carbon-based materials, transition metal oxides, transition metal chalcogenides, and multiple composites that were made of three or more semiconductor materials for photocatalytic water splitting.

scholarly journals Evaluation of nutritional value and microbiological safety in commercial dog food

2021 ◽  
Author(s):  
Katarzyna Kazimierska ◽  
Wioletta Biel ◽  
Robert Witkowicz ◽  
Jolanta Karakulska ◽  
Xymena Stachurska
Keyword(s):  
Nutritional Value ◽  
Microbiological Quality ◽  
Microbial Count ◽  
Pet Food ◽  
Microbiological Safety ◽  
Dog Food ◽  
Number Of Microorganisms ◽  
Contaminated Food ◽  
Dry Food

AbstractIn addition to properly balancing nutritional value in accordance with the needs of a dog, estimating the microbiological quality of dog food is crucial in providing healthy and safe foods. The aim of this study was to examine the quality of dry food for adult dogs, with particular reference to: (1) evaluating the nutritional value and compliance with nutritional guidelines for dogs, (2) comparing the nutritional value of dog foods, with particular emphasis on the division into cereal and cereal-free foods, and (3) evaluating their microbiological safety. All thirty-six evaluated dry dog foods met the minimum European Pet Food Industry FEDIAF requirement for total protein and fat content. The total aerobic microbial count in the analyzed dry dog foods ranged from 2.7 × 102 to above 3.0 × 107 cfu/g. In five (14%) dog foods the presence of staphylococci was detected; however, coagulase positive Staphylococcus (CPS) was not found. Mold presence was reported in one cereal-free dog food and in six cereal foods. In none of the analyzed foods Enterobacteriaceae were found, including coliforms, Escherichia coli and Salmonella spp. Bacteria of the genus Listeria and Clostridium as well as yeasts were also not detected. In conclusion, the evaluated dry dog foods had varied microbiological quality. The detected number of microorganisms may have some implications for long-term consumption of contaminated food. The lack of European Commission standards regarding the permissible amounts of microorganisms in pet food may result in insufficient quality control of these products.

scholarly journals Recent Advances of Photocatalytic Application in Water Treatment: A Review

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1804
Author(s):  
Guangmin Ren ◽  
Hongtao Han ◽  
Yixuan Wang ◽  
Sitong Liu ◽  
Jianyong Zhao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Water Treatment ◽  
High Efficiency ◽  
Low Cost ◽  
Great Promise ◽  
Rapid Progress ◽  
Recent Advances ◽  
Photocatalytic Application ◽  
Oxidation Technology ◽  
Performance Challenges

Photocatalysis holds great promise as an efficient and sustainable oxidation technology for application in wastewater treatment. Rapid progress developing novel materials has propelled photocatalysis to the forefront of sustainable wastewater treatments. This review presents the latest progress on applications of photocatalytic wastewater treatment. Our focus is on strategies for improving performance. Challenges and outlooks in this promising field are also discussed. We hope this review will help researchers design low-cost and high-efficiency photocatalysts for water treatment.

scholarly journals Adsorption of Carbon Dioxide by Reusing Drinking Water Treatment Plant Sludge

2017 ◽  
Vol 29 (12) ◽  
pp. 2665-2670
Author(s):  
Soleha Mohamat Yusuff ◽  
K.K. Ong ◽  
W.M.Z. Wan Yunus ◽  
A. Fitrianto ◽  
M. Ahmad ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Drinking Water Treatment Plant ◽  
Water Treatment Plant Sludge

scholarly journals Evaluation of an environmentally sustainable UV-assisted water treatment system for the removal of Bacillus globigii spores in water

2017 ◽  
Vol 18 (3) ◽  
pp. 968-975
Author(s):  
R. G. Silva ◽  
J. Szabo ◽  
V. Namboodiri ◽  
E. R. Krishnan ◽  
J. Rodriguez ◽  
...  
Keyword(s):  
Water Treatment ◽  
High Efficiency ◽  
Membrane Filter ◽  
Water Security ◽  
Disinfection Byproducts ◽  
Treatment System ◽  
Health Concern ◽  
Environmentally Sustainable ◽  
Inorganic Substances ◽  
The Impact

Abstract Development of greener water treatment technologies is important for the production of safe drinking water and water security applications, such as decontamination. Chlorine assisted disinfection is common and economical, but can generate disinfection byproducts (DBPs) that may be of health concern. DBPs are formed due to the reaction of chlorine with naturally occurring organic and inorganic substances in water. Currently, various innovative technologies are being developed as alternative approaches for preventing DBPs during water treatment. In this study, we evaluated the effectiveness of a novel combination of high efficiency flow filtration and UV disinfection treatment system for the removal of Bacillus globigii (B. globigii) spores in water. The filtration system consists of a charged membrane filter (CMF) that not only helps to remove suspended particles but also reduces the impact of other impurities including bio organisms. In order to get most performance details, the CMF was evaluated at clean, half-life, and end of life (EOL) conditions along with 100% UV transmittance (UVT). In addition, the effectiveness of the UV system was evaluated as a stand alone system at 100% and 70% EOL intensity. The study was conducted at the US EPA's Test and Evaluation (T&E) Facility in Cincinnati, OH, using B. globigii, a surrogate for B. anthracis spores. This non-chemical environmentally-friendly CMF/UV combination system and the stand alone UV unit showed greater than 6.0 log removal of B. globigii during the tests.

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